ASTM C756-87(1999)

Standard Test Method for Cleanability of Surface Finishes

SCOPE
1.1 This test method covers the numerical evaluation of the ease or difficulty of cleaning soiled surface finishes. This test method is applicable to all surface finishes not affected by water.  
1.2 Values given in SI units are to be regarded as the standard. Inch-pound units are provided for information only.  
1.3 This standard does not purport to address all of the safety problems associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

General Information

• Status: Historical
• Publication Date: 27-Aug-1987
• ICS: 25.220.20 - Surface treatment
• Technical Committee: B08 - Metallic and Inorganic Coatings
• Drafting Committee: B08.12 - Materials for Porcelain Enamel and Ceramic-Metal Systems

Relations

• Replaced By: ASTM C756-87(2006) - Standard Test Method for Cleanability of Surface Finishes
• Effective Date: 01-Apr-2006
• Referred By: ASTM C286-22 - Standard Terminology Relating to Porcelain Enamel and Ceramic-Metal Systems
• Effective Date: 28-Aug-1987

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation:C756–87 (Reapproved 1999)
Standard Test Method for
Cleanability of Surface Finishes
This standard is issued under the fixed designation C 756; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope 4. Significance and Use
1.1 This test method covers the numerical evaluation of the 4.1 This test method was developed to guide the user in
ease or difficulty of cleaning soiled surface finishes. This test selecting a finish coating or material that is resistant to soiling
method is applicable to all surface finishes not affected by in a particular application.
water. 4.2 The numerical values derived by this test method
1.2 Values given in SI units are to be regarded as the enables the user to rank finish coatings and materials in regard
standard. Inch-pound units are provided for information only. to soil retention or ease of soil removal.
1.3 This standard does not purport to address all of the
5. Apparatus
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro- 5.1 Motor-Driven Lapping Plate, 203-mm (8-in.) diameter,
speed 163 r/min.
priate safety and health practices and determine the applica-
bility of regulatory limitations prior to use. 5.2 Automatic Polishing Unit, 11-s cycle, adjustable to
48-mm (1 ⁄8-in.) stroke.
2. Referenced Documents
5.3 Hypodermic Syringe, glass, 2-mL capacity, without
2.1 ASTM Standards: needle.
C 282 Test Method forAcid Resistance of Porcelain Enam- 5.4 Repeating Pipet, 0.025 mL (25 µl) capacity.
els (Citric Acid Spot Test) 5.5 Repeating Pipet, 10-mL capacity.
C 614 Test Method for Alkali Resistance of Porcelain 5.6 Desiccator approximately 254 mm (10 in.) diameter.
Enamels 5.7 Cleaning Head, brass, 57 mm (2 ⁄4 in.), with worm-
driven hose clamp for attachment of cleaning tissues (Fig. 1).
3. Summary of Test Method
5.8 Soiling Head, brass, 25 mm (1 in.) diameter, with
3.1 The test method consists of applying an exact amount of
25-mm (1-in.) diameter facing of polytetrafluoroethylene at-
a fluorescent water-soluble soiling agent to a specimen surface tached with a water-proof household cement (Fig. 1).
and then cleaning the surface with a reproducible machine- 5.9 Extraction Cell, fitted with a fluorosilicone O-ring, size
1 1
wiping technique. The soil remaining on the specimen after
3.2 by 57 mm ( ⁄8 by 2 ⁄4 in.) (Fig. 2).
wipingisextractedwithawatersolventandthefluorescenceof 5.10 Fluorometer, for measuring the fluorescence of solu-
the solution measured. A standard reference surface is treated
tions.
inasimilarmanner.Thecleanabilityindexofthesurfaceunder 5.11 0.9 Neutral Density Filter, 50.8 by 50.8 mm (2 by 2
testisexpressedastheratioofthefluorescenceofthesolutions
in.) glass mounted (transmission 12.5 %).
extracted from the test surface and from the standard reference 5.12 Beakers, borosilicate, 100-mL capacity.
surface. Cleanability indexes greater than 1.0 indicate that the
test surface is more difficult to clean than the standard
reference surface, while indexes less than 1.0 indicate that the Suitable lapping plates are available from Buehler Ltd., 2120 Greenwood St.,
Evanston, IL 60204, Struers, Inc., 20102 Progress Drive, Cleveland, OH, 44136; or
test surface is more easily cleanable than the standard of
other Metallurgical Supply Sources.
comparison.
An Olsen “S.M.” Automatic Polisher has been found suitable and is available
3.2 The soiling agent used consists of polyethylene glycol,
under the code name OLPOL from Struers, Inc., 20102 Progress Drive, Cleveland,
OH 44136.
a black dye, and a fluorescent tracer, each of which is readily
O-rings must be fluorosilicone polymer; consult Precision Associates, 742 N.
water soluble.
Washington Ave., Minneapolis, MN 55401; Parker Seal Co., 10567 W. Jefferson
Blvd., Culver City, CA 90230; & B. W. Rogers (Parker Dis.) 1000 Brookpark Rd.,
Cleveland, OH 44109. Also see other sources in Thomas Register under SEALS:
This test method is under the jurisdiction ofASTM Committee B-8 on Metallic “O” RINGS.Asuitable device for clamping the cell to a specimen is shown in Fig.
and Inorganic Coatings and is the direct responsibility of Subcommittee B08.12 on 3 and Fig. 5.
Materials for Porcelain Enamel and Ceramic-Metal Systems. Turner Fluorometer, Model 111 (Turner 111-003) available from Curtin
Current edition approved Aug. 28, 1987. Published October 1987. Originally Matheson Scientific, Inc., 10727 Tucker St., Beltsville, MD 20705, Sequoia-Turner
published as C 756 – 73. Last previous edition C 756 – 79. Dial Model 111, Fisher Scientific Co., 711 Forbes Ave., Pittsburg, PA 15219, and
Annual Book of ASTM Standards, Vol 02.05. other principal cities for both.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
C756–87 (1999)
Cleaning Head, Brass Soiling Head, Brass
Metric Equivalents
AB C D E F G H
1 5 7 3 5 3 3
in. 2 ⁄4 ⁄8 ⁄8 ⁄16 1 ⁄8 ⁄4 ⁄16
(mm) (57) (16) (22) (5) (25) (16) (19) (5)
FIG. 1 Cleaning and Soiling Heads
NOTE 1—The porcelain enamel covercoat used to coat the standard
6. Reagents and Materials
reference surface shall have the following characteristics: Acid Resis-
6.1 Cleaning Tissues, approximately 127 by 229 mm (5 by
tance:AA(Test Method C 282)Alkali Resistance: Maximum 1.55 mg/cm
9 in.).
wt. loss (Test Method C 614).
6.2 Potassium Carbonate.
8. Preparation of Standard Soil
6.3 Polyethylene Glycol, 400.
6.4 Uranine, water-soluble, USP.
8.1 The soiling agent shall consist of the following:
6.5 Keco Acid Black, B(F101).
Ingredient Weight %
6.6 Ethyl Alcohol. Polyethylene glycol 98
Keco Acid Black B 1
6.7 Mild Household Detergent, liquid.
Uranine, water-soluble 1
7. Test Specimens
8.2 The uranine shall be added to the polyethylene glycol in
7.1 The preferred specimen size is 114 mm (4 ⁄2 in.) square, food blender and mixed by alternate periods of mixing and
but any other size or shape may be used provided it can be
standing until the crystalline uranine appears to be completely
rotated on the lapping wheel and the smaller dimension is dissolved in the glycol. The black dye which obscures all else
between 102 and 127 mm (4 and 5 in.). Sharp or jagged edges shall be added last and thoroughly mixed in the blender. This
shall be filed or honed to prevent snagging of the cleaning soiling agent shall be stored in a tightly stoppered glass bottle
tissues during the mechanical cleaning process. at least overnight before use.
7.2 Twelvespecimensarerequiredtoevaluatethecleanabil-
9. Procedure
ity index, that is, six of the candidate surface, and six of a
9.1 Specimen Pretreatment—Scrub the specimens with a
porcelain enamel standard reference surface for cleanability.
cellulose sponge wet with a 1 % solution of a mild household
Porcelain enamel specimens are not damaged by the cleanabil-
detergent at room temperature. Rinse in turn with tap water,
ity test and may be cleaned and reused many times. Specimens
distilled water, and ethyl alcohol, and allow to dry in a
have been reused as many as 50 times without damage or solid
near-vertical position at room temperature. Store the washed
buildup.
and dried specimens overnight in a desiccator charged with a
saturated solution of potassium carbonate.
Cel-Fibe Wipes, Type 1745 or equivalent.
9.2 Conditioning of Cleaning Tissues—Cut a supply of
Uranine is the sodium salt of fluorescein, C H O Na .
20 10 5 2
tissues ample for use in specimen cleaning treatment in the
Awater-soluble fabric dye used principally for nylon, silk, and wool; available
from Keystone Aniline and Chemical Co., 321 N. Loomis, Chicago, IL 60607. following paragraph into approximately 102-mm (4-in.)
C756–87 (1999)
Metric Equivalents
AB C D E F G H I
1 1 1 1 1 5 1 7 1
in. ⁄16 ⁄8 ⁄64 2 ⁄2 1 ⁄4 ⁄8 ⁄16 1 ⁄8 2 ⁄8
(mm.) (1.6) (3.2) (0.4) (64) (32) (16) (1.6) (47) (54)
All surfaces to be plated with bright nickel.
FIG. 2 Brass Extraction Cell
squares and store overnight, before use, in a desiccator charged With the repeating pipet expel exactly 0.021 mL of distilled
with a saturated solution of potassium carbonate (relative water at the center of the tissue on the first cleaning head.
humidity approximately 45 %). Allow the tissues to remain in 9.3.2 Immediately place the cleaning head with tissue side
the desiccator until just prior to use. againstthesoiledspecimen,engagethespindle,andoperatefor
9.3 Soiling and Cleaning Treatments: 22 s (so that it will stop as well as start at the center of the
9.3.1 Lay out six specimens face up on a table. Homogenize specimen). Remove the cleaning head without sliding motion.
thesoilingagentbyup-endingseveraltimesbeforeuse.Fillthe Repeat the cleaning operation with the second tissue-covered
head,usingthesameamountofdistilledwaterandforthesame
hypodermic syringe with no needle attached with the soiling
agent by withdrawing the plunger. Expel this charge of soil 22-s period.
back into the soil bottle. Then fill the syringe again. Wipe the 9.3.3 Store the first soiled and cleaned specimen in a near
tipofthesyringewithacleaningtissueandexpelseveraldrops vertical position in a rack while applying exactly the same
into the soil bottle. Then, without rewiping the tip, hold the series of soiling and cleaning treatments to the five remaining
syringe vertically over a specimen and discharge one drop near specimens.
the center of each of the six specimens. Center the first 9.4 Water Extraction of the Soil Retained—Remove the
specimen on the lapping wheel and hold it in place by means small, often nonvisible, amounts of soil from the central
of adhesive tape across the specimen corners. Place the portion of the soiled and cleaned specimens with 10 mL of
polytetrafluoroethylene-faced soiling head on the soil, and distilled water in the O-ring sealed extraction cell by the
engage the spindle (Fig. 4) of the polishing unit. Operate the following sequence of operations within 30 min after soiling;
lapping wheel and the polishing unit for 1 min to distribute the place the first soiled and cleaned specimen, face up, in the
soil over the central portion of the specimen (Fig. 5). Remove center of the cell clamping frame. Place a clean and dry
the soiling head and clean it with tissue for reuse. Adjust the extraction cell (Fig. 2) on the center of the specimen so that the
spindle so that it rests over the center of the soil spot. Prepare O-ring defines the area to be extracted (Fig. 5). Clamp the cell
twocleaningheads57mm(2 ⁄4in.)diameter)bycoveringwith intheframewithalightpressurefromthewingnuts;introduce
fourthicknessesofcleaningtissuesclampedsmoothlyinplace. 10 mL of distilled water with the 10-mL repeating pipet, swirl
C756–87 (1999)
Metric Equivalents
AB C D E F G H I J K L M N
1 1 3 1 7 5 1 1 1 5 5
in. ⁄16 2 ⁄4 1 ⁄8 ⁄4 1 ⁄8 ⁄16 56 1 ⁄4 3 ⁄4 ⁄4 4 ⁄8 4 ⁄8 5
(mm) (1.6) (64) (35) (6.4) (47) (8) (127) (152) (32) (83) (6.4) (117) (117) (127)
FIG. 3 Device for Clamping Extraction Cell to Specimen
the water in the cell momentarily and let stand for 3 min, give print on the glass cuvette containing the solution to be
the solution in the cell another swirl and pour out into a clean measured may be more fluorescent than the unknown.
and dry 100 mL beaker; transfer a portion of the extract to a
9.7.2 Wash the glass beakers and the extraction cells before
clean, dry cuvette and place the cuvette in a rack until the other
and after use by brushing in a warm detergent solution; rinse
five extracts are ready for measurement in the fluorometer.
copiously with flowing tap water and then with distilled water.
9.5 MeasurementofFluorescence—Operatethefluorometer
The glass beakers may be oven dried. The extraction cells,
according to the manufacturer’s instructions. Measure and
without O-ring removal, may be wiped dry with clean tissue.
record the fluorescence of a distilled water blank. Measure and
Clean the syringe used for dispensing uniform amounts of soil
record in turn the fluorescence of the solutions extracted from
on the specimens immediately following use with tap water,
the specimens.
distilled water and alcohol, and dry the parts with tissue. Give
the glass cuvettes used for measuring fluorescent solutions
NOTE 2—If concentrated solutions give off-scale readings, a 0.9
several rinses with tap water and then alcohol, and allow to
neutral-density filter should be inserted between the fluorescing solution
and the photomultiplier. This filter transmits only 12.5 % of the light
drain in an inverted position in a holding rack. Discard the
emitted by the solution, reducing the fluroescence readings and bringing
tissue for wiping glassware and other equipment after one use.
them on scale. Redetermine the blank reading with the filter in place and
multiply the reduced reading by 8.0 which is 1 divided by the 12.5 %
10. Calculation of a Cleanability Index
transmission of the neutral density filter.
10.1 Subtract the measured fluorescence value for the dis-
9.6 Standard Reference Surface—Apply the test procedure
tilled water blank from the measured fluorescence value for
outlined in 7.1 through 7.5 to the Standard Reference Surfaces
each of the six test surfaces and the six standard reference
at least once during each testing day to obtain the average
surfaces. This will result in corrected fluorescence values for
fluorescence of solutions extracted from these specimens.
the six test surfaces and for the six standard reference surfaces.
9.7 Preferred Methods of Equipment Cleaning:
9.7.1 The successful use of the fluorimetric analytical tech- 10.2 Calculate the average of the corrected fluorescence
niques employed in this procedure demands that a scrupulous values for the six test surfaces and for the six standard
level of cleanliness be maintained throughout. An oily thumb- reference surfaces.
C756–87 (1999)
Metric Equivalents
AB C
1 1
in. 10 ⁄2 ⁄4
(mm.) (254) (13) (6.4)
FIG. 4 Spindle for Polisher
FIG. 5 Equipment Used in Soiling and Cleaning Specimens
10.3 Calculate the coefficient of variation of the corrected 10.4 Repeat the cleanability determinations on all six speci-
fluorescence values for the six test surfaces and for the six mens (either the test specimens or the six standard reference
standard reference surfaces. specimens) if the coefficient of variation is greater than 20 %.
C75
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